From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH 1/2] i2c: omap: convert to module_platform_driver() Date: Tue, 04 Jun 2013 11:29:34 -0700 Message-ID: <87zjv5zq41.fsf@linaro.org> References: <1366723151-23209-1-git-send-email-grygorii.strashko@ti.com> <1366723151-23209-2-git-send-email-grygorii.strashko@ti.com> <87fvwylxl8.fsf@linaro.org> <51ADD06B.3000201@ti.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <51ADD06B.3000201@ti.com> (Grygorii Strashko's message of "Tue, 4 Jun 2013 14:32:59 +0300") Sender: linux-omap-owner@vger.kernel.org To: Grygorii Strashko Cc: Tony Lindgren , Samuel Ortiz , Wolfram Sang , "Ben Dooks (embedded platforms)" , Santosh Shilimkar , linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-i2c@vger.kernel.org Grygorii Strashko writes: > Hi Kevin, > On 06/03/2013 11:59 PM, Kevin Hilman wrote: >> Grygorii Strashko writes: >> >>> The OMAP I2C driver has a relation to pinctrl-single driver. As result, >>> its probe will be deferred during system boot until late init time, >>> because the pinctrl-single is initizalized as moudle/device init time. >>> This, in turn, will delay initialization of all I2C devices (like mfd, >>> I2C regulators and etc.) and cause boot delay (more over, it can broken >>> initialization of drivers which are not ready to use deferred probe >>> mechanism yet, for example DSS). >>> >>> There are no sense to keep OMAP I2C initialization on subsys init layer >>> any more, hence shift it to module/device layer where the i2c <--> >>> pinctrl-single dependency is resolved in drivers/Makefile now. >>> >>> Cc: Wolfram Sang >>> Cc: "Ben Dooks (embedded platforms)" >>> Cc: Santosh Shilimkar >>> Cc: linux-omap@vger.kernel.org >>> Cc: linux-i2c@vger.kernel.org >>> Cc: linux-kernel@vger.kernel.org >>> >>> Signed-off-by: Grygorii Strashko >> Testing this patch with PATCH 1/2, the twl_rtc driver fails to correctly >> initialize on OMAP3: >> >> twl_rtc rtc.22: hctosys: invalid date/time >> >> instead of the expected result: >> >> twl_rtc rtc.22: setting system clock to 2000-01-01 00:00:00 UTC (946684800) >> >> so something is still not right for the init sequence. >> >> Kevin > I think, the root cause of the problem isn't this patch - it's just > yet another side effect > of using deferred probes :). I've taken a look on twl-rtc code and > found possible error place > static int __init twl_rtc_init(void) > { > if (twl_class_is_4030()) <------ here, > rtc_reg_map = (u8 *) twl4030_rtc_reg_map; > else > rtc_reg_map = (u8 *) twl6030_rtc_reg_map; > > return platform_driver_register(&twl4030rtc_driver); > } > In drivers/Makefile: > obj-$(CONFIG_RTC_LIB) += rtc/ <------ RTC is placed before I2C > obj-y += i2c/ media/ <----- and only here I2C bus > instantiates TWL-core device > and configures twl_priv->twl_id > > Thats why it's working on my OMAP4/twl6030 board. Could you check if > below fix will work on OMAP3: Yes, your fix works. Thanks for digging into it. Care to send a proper patch? Please be sure to send to Andrew Morton also, since he'll be the one to queue the RTC patch. > diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c > index 8751a52..aaa5015 100644 > --- a/drivers/rtc/rtc-twl.c > +++ b/drivers/rtc/rtc-twl.c > @@ -469,6 +469,11 @@ static int twl_rtc_probe(struct platform_device *pdev) > if (irq <= 0) > goto out1; > > + if (twl_class_is_4030()) > + rtc_reg_map = (u8 *) twl4030_rtc_reg_map; > + else > + rtc_reg_map = (u8 *) twl6030_rtc_reg_map; > + > ret = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG); > if (ret < 0) > goto out1; > @@ -610,11 +615,6 @@ static struct platform_driver twl4030rtc_driver = { > > static int __init twl_rtc_init(void) > { > - if (twl_class_is_4030()) > - rtc_reg_map = (u8 *) twl4030_rtc_reg_map; > - else > - rtc_reg_map = (u8 *) twl6030_rtc_reg_map; > - > return platform_driver_register(&twl4030rtc_driver); > } > module_init(twl_rtc_init); > > Unfortunately, I have no OMAP3 HW and can't check it. I suggest you find a Beagle or Gumstix/Overo type board someplace. There is an abundance of cheap OMAP3 hardware available. Kevin